Funds are requested to purchase a laser scanning confocal microscope. This system, the Zeiss LSM 510 Meta coupled to an Axiovert 200 MOT, will replace a 10-year-old LSM 410 system with 232 registered users from 29 departments. The requested system will be housed and administered by the Neuroscience Imaging Center (NIC), the oldest imaging core facility at our University. The NIC employs a full-time technician with 8 years of experience operating the LSM 410 confocal microscope. Projects from 8 major and 9 minor users are described. These projects will benefit from the improved optics and detection system of the LSM 510 Meta, resulting in improved capture of fluorochrome emission, spectral separation, reduced phototoxicity and the ability to do fluorescence resonance energy transfer (FRET) measurements. Projects of the major users include: Ca 2+ channel trafficking in hippocampal slices or cultures of rat and mice (Dr. Herlitze), role and mechanical function of myosin II during cell locomotion in human cancer cells (Dr. Egelhoff), development of new mouse strains as genetic based tools for brain serotonergic neuron studies (Dr. Deneris), regulation of 5-HT-receptor targeting and trafficking (Dr. Roth), role of dynamin interacting proteins in the endocytotic cycle in Drosophila melanogaster (Dr. Robinson), role of endocytosis in EGF receptor trafficking (Dr. Carlin), regulation of postnatal cerebellar differentiation (Dr. Siegel) and axon regeneration across glial scar (Dr. Silver).